Occurrence, serovars and antibiotic resistance of Salmonella spp. in retail ready-to-eat food products in some Chinese provinces

Ready-to-eat (RTE) food products have been involved in numerous outbreaks of salmonellosis; however, epidemiological studies and data concerning Salmonella spp. contaminants of these foods are lacking in China. During 2015.6-2016.6, a total of 300 retail RTE food products were collected from 15 provincial capitals of China to determine the prevalence of Salmonella spp. and investigate serovar distribution and antibiotic resis-tance of the recovered isolates. Overall, seven (2.3%) of the food samples were contaminated by Salmonella spp. and the MPN values ranged from 0.3 to >110 MPN/g. Of the 26 recovered Salmonella isolates, eight serovars and eight MLST patterns were detected, with Salmonella enterica serovar Derby ST40 being the most prevalent. All isolated Salmonella serovars have previously been implicated in human infections. Eighty percent of the isolates were resistant to at least one antibiotic class, and thirty percent were multidrug-resistant. The isolates had the highest resistance rates to tetracycline (70.0%), with tet(A) at 60.0% and tet(B) at 10.0%. The occurrence of Salmonella spp. and the high antibiotic-resistance rates of the isolates detected in the RTE foods could be po-tential human health risks. These results indicate that further supervision and hygienic regulations are needed in the RTE food production chain to ensure microbiological safety.

Automated summary

RTE food products in China were found to be contaminated with Salmonella spp., with the most prevalent serovar being Derby ST40; 80% of the isolates were resistant to at least one antibiotic class, while 30% were multidrug-resistant.